1. Field of the Invention
This invention relates to an interior illumination lamp suitably used in a vehicle.
2. Related Art
An interior illumination lamp, used for illuminating the inside of a vehicle room and for other illumination purposes as when making up the user's face, is mounted on a ceiling surface of the vehicle or a sun visor.
FIG. 6 shows a conventional interior illumination lamp 50 (see, for example, Unexamined Japanese Patent Publication 2003-95018). This interior illumination lamp 50 comprises a lamp base portion 51 for mounting on an interior member 54, and a lens 55 mounted on the lamp base portion 51.
As shown in FIG. 7, a plate portion 62 which can be bent at a hinge portion 56 is formed on and projects from a reverse surface 51a of the lamp base portion 51, and retaining ribs 63 which can be retainingly engaged respectively in holes 62a formed through the plate portion 62 are also formed on and project from the reverse surface 51a. The reverse surface 51a of the lamp base portion 51 and the bent plate portion 62 hold the interior member 54 therebetween, thereby mounting the lamp base portion 51 on the interior member 54.
In the conventional interior illumination lamp 50, however, at the time when the plate portion 62 is brought into retaining engagement with the retaining ribs 63 after these retaining ribs 63 pass respectively through the holes 62a, an excessive pressing force is applied from the plate portion 62 to the interior member 54 in a direction of the thickness of this interior member 54, so that the interior member 54 is squeezed, and therefore is subjected to plastic deformation. As a result, a gap is formed between the interior member 54 and the plate portion 62, which has invited a problem that a self-holding ability of the interior illumination lamp is lowered.